I am in love with my V shaped pillow. Not just for sleeping but because I've been most comfortable reclining all day, so have been mostly in bed!
Several pairs of button down pyjamas because washing yourself is a little tricky so it's nice to have fresh PJs every day. In hindsight I wish I'd bought a couple of button down tops for when I was ready to venture out of bed. Getting my arms above my head is still a bit of a struggle (2 weeks in), so I would have liked tops which button or zip at the front. Having been big boobed I don't own any of those!
I'm glad I had a couple of styles of bra. I got the Asda ones and the M&S ones. I've found that they all touch my boobs in different places, so it's nice to be able to have options when one starts to feel irritating against my skin. This might just be me though.
Doing my hair is still not possible, so I wish I'd taught my husband to do hair before the op! And I'd have bought some dry shampoo.
Other than that, plenty of easy snacks you can keep by the bed (grapes were good for me) and stuff to keep you moving like prune juice.
Good luck!